1. Field of the Invention
The present invention relates generally to a series fan assembly structure, and more particularly to a series fan assembly structure, which can be quickly assembled at higher axial and radial connection tightness.
2. Description of the Related Art
Along with the advance of sciences and technologies, the reliance of peoples on various electronic apparatuses has more and more increased. In operation, the internal components of the electronic products (such as computers and laptops) will generate high heat. The heat must be dissipated to outer side of the electronic products in time. Otherwise, the problem of overheating will take place. Therefore, most of the electronic products are provided with fans disposed therein for keeping the electronic products working at an operation temperature within a range. However, in some cases, the air volume provided by one single fan is sufficient. To overcome this problem, two or more fans are often serially assembled to provide sufficient air volume.
For example, Taiwanese Patent Publication No. 481434 discloses a cooling device for a central processing unit. The cooling device includes radiating fins and at least two fans. The cooling device is characterized in that the first and second fans are serially mated with each other to form a series fan. Several connection posts are disposed between the first and second fans to space the first and second fans by a certain distance. Accordingly, when the radiating fins absorb the high heat generated by the central processing unit, the series fan provides larger wind pressure and larger air volume so as to speed heat dissipation and enhance cooling effect.
In the above patent, the four corners of the fan frame of each fan are formed with through holes. Accordingly, screws can be passed through the through holes of the fans to serially connect the fans and lock the fans on the radiating fins.
In practice, the fans cannot be securely serially connected simply by means of the screws. This is because when locked with the screws, the forced points reside on one side of one fan, rather than on the connection faces of both fans. Therefore, the serial connection force is insufficient. As a result, the fans tend to make noise in operation. Also, the fluid is likely to escape from the gap between the connection faces. This will affect the air volume acting on the heat sink and deteriorate the heat dissipation performance.
Moreover, the cost for the conventional structure for fixing the series cooling fan is higher. In addition, the conventional series cooling fan has insufficient assembling strength and poor tightness. After assembled, the series cooling fan is likely to radially and axially vibrate. Accordingly, in the case that the fan operates at high rotational speed or is applied to an environment of a server or a telecommunication chassis, the fan is apt to loosen or detach.
Another type of conventional series cooling fan is assembled in another manner. One of the fans to be serially assembled has multiple through holes on four corners, while the other fan has at least one boss body positioned in a position in alignment with the through hole. The boss body is correspondingly inserted into the through hole to fixedly serially connect the two fans. However, by means of the above fixing measure, the series cooling fan still cannot be tightly connected. As a result, the series cooling fan is still likely to vibrate and make noise.
According to the above, the conventional technique has the following shortcomings:
1. The tightness of the conventional series fan is poor.
2. The conventional series fan is likely to vibrate and make noise.
3. The conventional series fan is hard to assemble.